不同耕作模式对玉米田土壤杂草种子库的影响

Effects of Different Tillage Patterns on Soil Weed Seedbank in Maize Field

[目的]为明确不同耕作模式对玉米田土壤杂草种子库的影响,研究翻耕和免耕模式下玉米田杂草种子库的组成和特征。[方法]采用杂草种子萌发法,将0-5、5-10、10-15、15-20、20-25、25-30 cm 6个不同土层的土壤样本分别装盆,在自然条件下生长60 d后调查杂草种类和数量,计算种子库的密度和相对优势度。[结果]翻耕玉米田共有杂草15科24种,免耕玉米田有15科23种,其中19种杂草在翻耕和免耕玉米田均有分布,主要优势杂草为稗草、藜、铁苋菜、龙葵和马唐,杂草类型上以阔叶杂草为主,禾本科杂草较少。翻耕玉米田杂草种子库总密度为4 292.4粒/m^2,主要分布在0-5、20-25、25-30 cm土层,其中稗草的密度和相对优势度最高;免耕玉米田总密度为3 337.0粒/m^2,主要分布在15-20、20-25 cm土层,其中藜的密度和相对优势度最高。不同耕作模式的优势杂草在土层中的分布有较大差别,稗草在翻耕田主要分布于25-30 cm土层,而在免耕田主要分布于0-5 cm土层;藜在免耕田主要分布于20-25cm土层,而在翻耕田各土层呈较均匀分布。[结论]明确了不同耕作模式土壤杂草种子库的组成和特征,为农田杂草的综合管理提供理论依据。

[Objective] Field studies were conducted to evaluate the effects of two different tillage patterns,plowing and no-tillage,on the characteristics and the composition of soil weed seedbank.[Method] By using the method of weed seed germination,the 0-5,5-10,10-15,15-20,20-25,25-30 cm of 6 different soil samples were put into pots,the species and quantity of weeds were investigated after growing 60 d under natural conditions,and then calculate the density and relative dominance of seed bank.[Result]The results showed that,a total of 24 weed species belonging 15 families in the plowing maize field,and 23 weed species belonging 15 families in the no tillage maize field. There were 19 kinds of weeds in plowing and no-tillage maize field. The main advantage weeds were Echinochloa crus-galli（ L.）,Chenopodium album Linn.,Acalypha australis L.,Solanum nigrum L. and Digitaria sanguinalis（ Linn.） Scop. Broad leaved weeds are the main weeds,less gramineous weeds in the type of weeds. The density of weed seed bank is 4 292. 4 grains / m^2,more weeds located in 0-5,20-25,25-30 cm and the density and the relative advantages of E. c. is the highest in plowing maize field. The density of weed seed bank is 3 337. 0 grains / m^2,more weeds located in the soil layer of 15-20,20-25 cm and the density and the relative advantages of Ch. a. is the highest in no-tillage maize field. There are quite different in the soil distribution of dominant weed species. E. c. mainly distributed in 25-30 cm under the plowing maize field,and it is in the 0-5 cm soil layer under no-tillage field. Ch. a. mainly distributed in 20-25 cm under the no-tillage plowing maize field,and it showed a uniform distribution in the plowing field.[Conclusion] The composition and characteristics of soil weed seed bank in different tillage patterns were defined,which provided theoretical basis for integrated management of weeds in farmland.